CVE-2017-3645 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: Optimizer). Supported versions that are affected are 5.7.18 and earlier. Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. CVSS 3.0 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 01/04/2021
The vulnerability identified as CVE-2017-3645 resides within the MySQL Server component of Oracle MySQL, specifically within the Server: Optimizer subcomponent. This flaw affects MySQL versions 5.7.18 and earlier, representing a significant security concern for database administrators and system operators who rely on MySQL for critical data operations. The vulnerability's classification as easily exploitable indicates that attackers with relatively low barriers to entry can leverage this weakness, making it particularly dangerous in production environments where database availability is paramount. The affected version range suggests this issue was present in a substantial portion of MySQL deployments during the period when this vulnerability was actively exploited.
The technical nature of this vulnerability stems from a flaw in the query optimizer's handling of specific SQL operations, which creates conditions that can lead to system instability. When an attacker with high privileges and network access executes carefully crafted queries against the MySQL server, the optimizer component fails to properly manage memory or execution flow, resulting in system hangs or repeated crashes. This behavior constitutes a complete denial of service condition that can render the database server unavailable for legitimate operations. The vulnerability's impact is amplified by the fact that it requires only high privileged access rather than administrative credentials, suggesting that users with database-level privileges can trigger the exploit. The CVSS 3.0 scoring of 4.9 reflects the availability impact severity, with a base score that indicates moderate to high risk.
The operational impact of CVE-2017-3645 extends beyond simple service disruption to potentially compromise entire database infrastructure availability. Organizations relying on MySQL for mission-critical applications face significant business risk when this vulnerability exists in their environment, as database downtime can cascade into broader system failures. The vulnerability's ability to cause frequently repeatable crashes means that even a single successful exploitation attempt can render the database server unusable until manual intervention occurs. This type of vulnerability directly impacts the database availability and reliability requirements that organizations typically establish for their infrastructure. The fact that the attack vector requires network access via multiple protocols suggests that the vulnerability could be exploited from various entry points, increasing the attack surface and making it more difficult to defend against.
Organizations should prioritize immediate remediation through patch management processes that upgrade affected MySQL installations to versions beyond 5.7.18. The vulnerability's classification under CWE-121, which addresses buffer overflow conditions, indicates that proper input validation and memory management practices should be implemented as defensive measures. Additionally, implementing network segmentation and access controls can help limit the attack surface by restricting which users or systems can access the MySQL server. The ATT&CK framework's T1499 technique for network denial of service operations applies directly to this vulnerability, as it enables attackers to disrupt database availability through controlled exploitation. Security monitoring should include detection of unusual query patterns that might indicate exploitation attempts, while regular vulnerability assessments should verify that all MySQL installations have been updated to secure versions. The remediation process should also include comprehensive testing of patched environments to ensure that the fix does not introduce compatibility issues with existing database applications and services.